Solve Sudoku

Sudoku was a game which has 9 columns and 9 rows and separated with 9 subsystem 3 column X3 row. The rule :
• Each column must fill 1 – 9 number, cannot be repeated.
• Each row must fill 1 – 9 number, cannot be repeated.
• Each subsystem must fill 1 – 9 number, cannot be repeated.
So, this game need to use Logic. Based on my experience there some clue
 When you found row or column of subsystem fill with X number two times, 3rd X number must be in the other subsystem
 When the row or column of subsystem fulfill with number, then the number outside of row or column in subsystem will be part of row or column in system.
 You can use eliminate number if the number exist in column or row or subsystem because can be repeat again.
 Calculate of probability number will appear.
 Complete Fill number if there in subsystem or column or row three number remain.
Last think, as reference to standard Sudoku, if you can finish before ten minute it mean you are genius, if you can finish between ten to fifteen minute it mean you smart, if you finish above fifteen minute it means you average.